What is Gynecomastia?

Gynecomastia is benign enlargement of male breast tissue. It's caused by an imbalance between estrogen (which stimulates breast growth) and testosterone (which inhibits it). It can affect one or both breasts.

Normal ("Physiologic") Gynecomastia:

• Newborns: Due to maternal estrogen exposure; resolves within weeks
• Puberty: Affects 50-60% of adolescent boys (age 12-14); usually resolves within 1-2 years
• Aging: Common in older men due to decreased testosterone and increased body fat (which converts testosterone to estrogen)

Pathologic Causes:

Medications (Most Common Cause in Adults):

• Spironolactone (anti-androgen)
• Finasteride, dutasteride (5-alpha reductase inhibitors)
• Anti-androgens (bicalutamide, flutamide)
• Anabolic steroids (when stopped, estrogen rebounds)
• Opioids, marijuana
• Cimetidine (H2 blocker)
• Calcium channel blockers, digoxin
• Antipsychotics, antidepressants

Hormonal Disorders:

• Hypogonadism: Low testosterone (primary or secondary)
• Hyperthyroidism: Increases SHBG, shifting estrogen/testosterone ratio
• Tumors: Testicular (hCG-secreting), adrenal, pituitary (prolactinoma)
• Klinefelter Syndrome (XXY): Low testosterone, high estrogen

Other Causes:

• Liver disease (cirrhosis)—impaired estrogen metabolism
• Kidney failure (dialysis)
• Malnutrition/refeeding
• HIV/AIDS

Differentiating Gynecomastia from Pseudogynecomastia:

• Gynecomastia: Firm, rubbery glandular tissue beneath the nipple (feels like a disc)
• Pseudogynecomastia: Soft fatty tissue without glandular enlargement (common in obesity)

When to Worry (Red Flags for Breast Cancer):

• Unilateral, hard, fixed mass
• Nipple discharge (bloody)
• Skin changes (dimpling, ulceration)
• Lymph node enlargement
• Rapid growth

Evaluation:

History: Onset, duration, medications, alcohol/drug use, symptoms of hypogonadism or hyperthyroidism

Physical Exam: Testicular exam (size, masses), breast exam (glandular vs. fatty tissue)

Labs (if pathologic cause suspected):

• Testosterone (total and free)
• LH, FSH
• Estradiol
• hCG (betahCG)—if testicular tumor suspected
• TSH, prolactin
• Liver function tests, kidney function
• Karyotype (if Klinefelter suspected)

Imaging:

• Testicular ultrasound (if exam abnormal or hCG elevated)
• Mammogram (if concern for breast cancer)

Treatment:

Observation:

• Pubertal gynecomastia usually resolves spontaneously within 1-2 years
• If gynecomastia present <1 year, there's still a chance for regression

Treat Underlying Cause:

• Stop offending medication (if possible)
• Testosterone replacement (if hypogonadal)
• Treat hyperthyroidism
• Remove tumor

Medical Therapy (Limited Efficacy):

• Tamoxifen: Selective estrogen receptor modulator; most evidence (20 mg/day for 3-6 months)
• Raloxifene: Alternative SERM
• Aromatase Inhibitors (Anastrozole): Block estrogen production; less effective in established gynecomastia
• Medical therapy works best if started early (<12 months duration)

Surgery:

• Indications: Severe, persistent (>12 months), psychologically distressing gynecomastia unresponsive to medical therapy
• Procedures: Liposuction (for fatty tissue), mastectomy (for glandular tissue), or combination
• High patient satisfaction rates